1. Field of the Invention
The present invention relates to a semiconductor device which transmits and receives data by a radio signal.
2. Description of the Related Art
In recent years, a compact semiconductor device (hereinafter, an RF tag) that is a combination of an ultra compact IC chip and an antenna for wireless communication has received a lot of attention. The RF tag is known as an information medium which incorporates a semiconductor memory and which can read information stored in the semiconductor memory or can write information in the semiconductor device by radio waves from a wireless communication device (hereinafter, a reader/writer).
For example, an RF tag in which a communication circuit, a signal control circuit, and a memory portion are formed in a semiconductor integrated circuit and they are combined with an antenna is disclosed (e.g., refer to Patent Document 1).
As an application field of the RF tag, merchandise management in the distribution industry is given as an example. Although merchandise management utilizing a barcode has been a mainstream recently, since a barcode including data is read optically, data cannot be read when there is a shield. On the other hand, since the RF tag reads data wirelessly, the data can be read even if there is a shield as long as radio waves are transmitted. Consequently, an improvement in efficiency and reduction in cost of merchandise management, and the like are expected. In addition, the RF tag is expected to be widely applied to, for example, train tickets, airplane tickets, and automatic resets.    Patent Document 1: Japanese Published Patent Application No. 2005-202947